<title>求最大公约数</title><link href="http://hzoi.com/tomorrow.css" rel="stylesheet"><div class="ui existing segment"><pre><code><span class="pl-cp">#include</span><span class="pl-cpf">&lt;cstdio&gt;</span><span class="pl-cp"></span>
<span class="pl-kt">int</span> <span class="pl-nf">f</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">a</span><span class="pl-p">,</span><span class="pl-kt">int</span> <span class="pl-n">b</span><span class="pl-p">);</span>
<span class="pl-kt">int</span> <span class="pl-nf">main</span><span class="pl-p">(){</span>
	<span class="pl-n">freopen</span><span class="pl-p">(</span><span class="pl-s">&quot;gcd.in&quot;</span><span class="pl-p">,</span><span class="pl-s">&quot;r&quot;</span><span class="pl-p">,</span><span class="pl-n">stdin</span><span class="pl-p">);</span>
	<span class="pl-n">freopen</span><span class="pl-p">(</span><span class="pl-s">&quot;gcd.out&quot;</span><span class="pl-p">,</span><span class="pl-s">&quot;w&quot;</span><span class="pl-p">,</span><span class="pl-n">stdout</span><span class="pl-p">);</span>
		<span class="pl-kt">int</span> <span class="pl-n">a</span><span class="pl-p">,</span><span class="pl-n">b</span><span class="pl-p">;</span>
		<span class="pl-n">scanf</span><span class="pl-p">(</span><span class="pl-s">&quot;%d%d&quot;</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">a</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">b</span><span class="pl-p">);</span>
		<span class="pl-n">printf</span><span class="pl-p">(</span><span class="pl-s">&quot;%d&quot;</span><span class="pl-p">,</span><span class="pl-n">f</span><span class="pl-p">(</span><span class="pl-n">a</span><span class="pl-p">,</span><span class="pl-n">b</span><span class="pl-p">));</span>
		<span class="pl-k">return</span> <span class="pl-mi">0</span><span class="pl-p">;</span>
<span class="pl-p">}</span>
<span class="pl-kt">int</span> <span class="pl-nf">f</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">a</span><span class="pl-p">,</span><span class="pl-kt">int</span> <span class="pl-n">b</span><span class="pl-p">){</span>
        <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">a</span><span class="pl-o">&lt;</span><span class="pl-n">b</span><span class="pl-p">)</span><span class="pl-k">return</span> <span class="pl-n">f</span><span class="pl-p">(</span><span class="pl-n">b</span><span class="pl-p">,</span><span class="pl-n">a</span><span class="pl-p">);</span>
        <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">a</span><span class="pl-o">%</span><span class="pl-n">b</span><span class="pl-o">==</span><span class="pl-mi">0</span><span class="pl-p">)</span><span class="pl-k">return</span> <span class="pl-n">b</span><span class="pl-p">;</span>
        <span class="pl-k">return</span> <span class="pl-n">f</span><span class="pl-p">(</span><span class="pl-n">b</span><span class="pl-p">,</span><span class="pl-n">a</span><span class="pl-o">%</span><span class="pl-n">b</span><span class="pl-p">);</span>
<span class="pl-p">}</span>
</cpde></pre></div>